Auto compared to Manual
Submitted: Tuesday, May 13, 2008 at 14:41
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57565
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Member - DAZA (QLD)
Hi All
On a previous thread, some one was asking the benifits of Automatic
compared to Manual, with 4x4-s, one of the replys was that Manuals
have better engine brakeing capacity on steep grades ect when towing, I was wondering why cant you use the T-Bar on the Autos
to drop it down to 1st or 2nd gear on a steep grade, for engine
brakeing, I havent towed Caravans with an Automatic as yet, but
will be buying a Automatic Nissan Patrol in the near future, and
would appreciate your input.
Cheers
Daza
Reply By: Philip A - Tuesday, May 13, 2008 at 15:54
Tuesday, May 13, 2008 at 15:54
Autos usually have a much higher low low , as the torque converter provides a lot of torque multiplication in low low for acceleration.
In general autos do not work
well with really low gearing, as they change into top very quickly and sharply.
In my Range Rover 3.9 , I think the low low is about 30:1 vs the manual at 40:1. The older autos also do not lock the TC in low low, although some newer ones do.
This means that autos tend to run away much more than a manual, however in these days of "
Hill descent" or the numerous other similar systems, it doesn't matter so much. I do not have any electronic help, but disc brakes can also be much easier modulated than old drums.
In every other situation an auto is far superior. In sand you do not have to worry about changing gear, as power continues to be applied on gearchange so you do not stop. At
rock steps, the TC absorbs the shock as you hit a step.
Regards Philip A
AnswerID:
303593
Reply By: MrBitchi (QLD) - Tuesday, May 13, 2008 at 15:58
Tuesday, May 13, 2008 at 15:58
Depends a bit on the type of auto. The ones with "tiptronic" or "sports" mode are very good as when you select a lower gear it changes down if at all possible, and will hold that gear, just like a manual. The standard auto's can be a bit reluctant to change down.
I have both types' a '95 model Statesman 4 speed auto and a Pajero NM with sports mode. The Paj can be driven like a manual but the Statesman's transmission is a dinosaur by comparison.
When going down steep descents in the Paj, 4L 1st gear will accommodate most situations but you do tend to have to feather the brakes a bit, so yes, a diesel manual is generally better down STEEP hills, especially when towing, although a properly sorted brake package on the trailer should fix most problems.
In every other conceivable situation the Paj auto is superior to a manual, IMHO.
AnswerID:
303596
Follow Up By: Member - Serg (VIC) - Friday, May 16, 2008 at 15:52
Friday, May 16, 2008 at 15:52
“will hold that gear, just like a manual”
In most situation it will not. In each and every AT what I have tried (and I specifically
check this particular point) there is “idiot proof” “feature” that kick tranny to 2-nd once car hit 40 km/hr or so. There is no remedy, but press break. Besides noise what AT produces when it “breaks” at 30 km/hr is absolutely horrible. Autos completely sux in breaking department.
FollowupID:
570227
Follow Up By: MrBitchi (QLD) - Friday, May 16, 2008 at 16:13
Friday, May 16, 2008 at 16:13
You obviously haven't driven a late model Pajero. It WILL hold the gear. It will NOT change up.
FollowupID:
570234
Follow Up By: Member - Serg (VIC) - Friday, May 16, 2008 at 16:21
Friday, May 16, 2008 at 16:21
No I did not. But I have driven latest “sequential-sport-shift” 380 and it does shift up. Are you talking about low-range or high-one? In low it probably has much more tolerance because too much oil to stir and to many cogs to spin. But I bet if you manage to make 5000 rpm from engine, auto will shift.
Serg
FollowupID:
570237
Follow Up By: MrBitchi (QLD) - Friday, May 16, 2008 at 16:34
Friday, May 16, 2008 at 16:34
In manual mode the engine will rev to the redline and NOT change up. Have done this accidentally in both low and high range. Sometimes I forget I'm in manual mode (much embarrassment ;-PP )
FollowupID:
570239
Reply By: Sand Man (SA) - Tuesday, May 13, 2008 at 15:59
Tuesday, May 13, 2008 at 15:59
You can drop down to 1st gear, low range, but the idle speed plus I think a bit of slippage from the torque converter doesn't always allow the engine breaking to overcome the mass weight of the vehicle.
It's not a major issue, just requires you to sometimes "ride the brake" which I am none too keen on, but have no choice, as
mine is an auto.
On the plus side, you do not need to be experienced in "stall starting" going up a steep gradient, so that is an advantage over the manual transmission.
All in all, the auto is not an adverse choice. Go for it mate.
Bill.
AnswerID:
303597
Reply By: Angler - Tuesday, May 13, 2008 at 20:58
Tuesday, May 13, 2008 at 20:58
I find one of the big advantages is I don't have to change gears, the box does it for me. I remember once I was traveling with another couple of blokes and they were in a manual V6 paj. The trip was to the cape and as many know there are big mobs of sandy patches in most of the crossings that require the experienced driver to slow and select about second gear. When we arrived
Bamaga the bloke driving the paj commented his arm was suffering because of the many gear changes. On the other hand I hardly changes at all and let the auto do all the work for me. The engine kept spinning at about 2000rpm most of the time and the auto took up the slack without any problems.
Everyone knows the auto is far superior in sand compared to a manual. I for one will never go back to a manual. My last three 4WD's were auto as is the family runabout.
Pooley
AnswerID:
303663
Reply By: Robin Miller - Wednesday, May 14, 2008 at 10:33
Wednesday, May 14, 2008 at 10:33
Hi Daza
Most of these things like auto/manual don't really matter when it doesn't really count.
And so these things need to be evaluated at the limits.
In the case of holding in lower gear with an auto many cars can do this but will still upchange into disaster when the engine revs reach there limit and this is often beyond your control.
Patrol 5 speed auto does this - so
check situation with car your thinking of.
Another "sleeper" issue to watch, is the ease of which foot slips
from brake to accel under adverse conditions.
AnswerID:
303723